Seed delivery apparatus, systems, and methods

ABSTRACT

A seed delivery apparatus and methods in which a seed conveyor delivers seed from a metering device to a furrow in a controlled manner to maintain seed placement accuracy within the furrow.

BACKGROUND

In recent years, the agricultural industry has recognized the need toperform planting operations more quickly due to the limited time duringwhich such planting operations are agronomically preferable or (in somegrowing seasons) even possible due to inclement weather. However,drawing a planting implement through the field at faster speedsincreases the speed of deposited seeds relative to the ground, causingseeds to roll and bounce upon landing in the trench and resulting ininconsistent plant spacing. The adverse agronomic effects of poor seedplacement and inconsistent plant spacing are well known in the art.

As such, there is a need for apparatus, systems and methods ofeffectively delivering seed to the trench while maintaining seedplacement accuracy at both low and high implement speeds.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of a prior art row unit of anagricultural row crop planter.

FIG. 2A is a side elevation view of an embodiment of a seed conveyor incooperation with a seed disc.

FIG. 2B is a partial side elevation view of an embodiment of a seedconveyor in cooperation with a seed disc.

FIG. 2C is a partial side elevation view of an embodiment of a seedconveyor depositing seeds in a seed trench.

FIG. 2D is a side elevation view of an embodiment of a seed conveyor incooperation with a seed disc.

FIG. 2E is a side elevation view of an embodiment of a seed conveyor incooperation with a seed disc.

FIG. 3 is a partial side elevation view of an embodiment of a seedconveyor in cooperation with a seed disc.

FIG. 4A is a side elevation view of an embodiment of a seed conveyor incooperation with a seed disc.

FIG. 4B is a partial side elevation view of an embodiment of a seedconveyor in cooperation with a seed disc.

FIG. 4C is a partial side elevation view of an embodiment of a seedconveyor in cooperation with a seed disc.

FIG. 5A is a partial side elevation view of an embodiment of a seedconveyor in cooperation with an embodiment of a seed sensor.

FIG. 5B is a partial front elevation view of an embodiment of a seedconveyor in cooperation with an embodiment of a seed sensor.

FIG. 5C is a side elevation view of an embodiment of a seed conveyor.

FIG. 5D is a partial side elevation view of an embodiment of a seedconveyor in cooperation with an embodiment of a seed sensor.

FIG. 5E is a view of an embodiment of a seed sensor in cooperation withan embodiment of a seed conveyor along section 5E-5E of FIG. 5D.

FIG. 5F is a partial side elevation view of an embodiment of a seedconveyor in cooperation with an embodiment of a seed sensor and a seeddisc.

FIG. 6A is a partial side elevation view of a seed disc in cooperationwith an embodiment of a seed sensor in cooperation with an embodiment ofa seed disc and an embodiment of a seed conveyor.

FIG. 6B is a partial front elevation view of an embodiment of a seeddisc in cooperation with an embodiment of a seed sensor.

FIG. 6C is a partial front elevation view of an embodiment of a seeddisc in cooperation with an embodiment of a seed sensor.

FIG. 7A is a partial side elevation view of an embodiment of a seedconveyor in cooperation with an embodiment of a seed sensor.

FIG. 7B is a partial front elevation view of an embodiment of a seedsensor in cooperation with an embodiment of a seed conveyor.

FIG. 8A is a schematic illustration of an embodiment of a seed conveyorcontrol system.

FIG. 8B illustrates an embodiment of a seed conveyor control system.

FIG. 9A illustrates an embodiment of a process for controlling a seedconveyor.

FIG. 9B is a top view of a tractor in cooperation with an embodiment ofa planter.

FIG. 9C is a top view of a tractor in cooperation with an embodiment ofa planter.

FIG. 9D illustrates an embodiment of a process for determining a localspeed along a toolbar.

FIG. 9E illustrates a calibration curve for controlling a seed conveyor.

FIG. 10A illustrates an embodiment of a process for controlling a seedconveyor.

FIG. 10B is a side elevation view of an embodiment of a seed conveyortraversing a field.

FIG. 10C illustrates an embodiment of a process for controlling a seedconveyor.

FIG. 10D is a side elevation view of an embodiment of a seed conveyortraversing a field.

FIG. 11A is a side elevation view of an embodiment of a planter row unitin cooperation with an embodiment of a seed conveyor.

FIG. 11B is a perspective view of a seed conveyor in cooperation with anembodiment of a seed meter.

FIG. 11C is a perspective view of a seed conveyor in cooperation with anembodiment of a seed meter.

FIG. 11D is a front elevation view of an embodiment of a seed conveyorin cooperation with an embodiment of a seed disc.

FIG. 11E is a side elevation view of an embodiment of a seed conveyor incooperation with an embodiment of a seed disc.

FIG. 12A is a side elevation view of another embodiment of a seedconveyor with certain components removed for clarity.

FIG. 12B is a side perspective view of the seed conveyor of FIG. 12Awith certain components removed for clarity.

FIG. 12C is a cross-sectional view of the seed conveyor of FIG. 12A incommunication with an embodiment of a seed disc.

FIG. 12D is a cross-sectional view of the seed conveyor of FIG. 12A incommunication with another embodiment of a seed disc.

FIG. 12E is a perspective cross-sectional view of the seed conveyor ofFIG. 12A in communication with the seed disc of FIG. 12C.

FIG. 12F is a perspective view of the seed conveyor of FIG. 12A withcertain components removed for clarity.

FIG. 12G is a left side elevation view of the seed conveyor of FIG. 12Awith certain components removed for clarity.

FIG. 12H is a right side elevation view of the seed conveyor of FIG. 12Awith certain components removed for clarity.

FIG. 12I is a perspective view of the gearbox of the seed conveyor ofFIG. 12A.

FIG. 12J is a partial right elevation view of the seed conveyor of FIG.12A in communication with an embodiment of a seed meter.

FIG. 12K is a partial right perspective view of the seed conveyor ofFIG. 12A in communication with the seed meter of FIG. 12J.

FIG. 12L is a partial left elevation view of the seed conveyor of FIG.12A in communication with the seed meter of FIG. 12J, with certaincomponents removed for clarity.

FIG. 12M is a cross-sectional view of the seed conveyor of FIG. 12A incommunication with the seed disc of FIG. 12C.

FIG. 13 is partial side elevation view of a row unit shank supportingthe seed conveyor of FIG. 12A.

FIG. 14 is a partial side elevation view still another embodiment of aseed conveyor including a loading wheel.

FIG. 15 illustrates a process for operating a seed conveyor havingloading wheels.

DESCRIPTION

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views, FIG. 1illustrates a side elevation view of a single row unit 10 of aconventional row crop planter such as the type disclosed in U.S. Pat.No. 7,438,006, the disclosure of which is hereby incorporated herein inits entirety by reference. As is well known in the art, the row units 10are mounted in spaced relation along the length of a transverse toolbar12 by a parallel linkage 14, comprised of upper and lower parallel arms16, 18 pivotally mounted at their forward ends to the transverse toolbar12 and at their rearward end to the row unit frame 20. The parallellinkage 14 permits each row unit 10 to move vertically independently ofthe toolbar 12 and the other spaced row units in order to accommodatechanges in terrain or rocks or other obstructions encountered by the rowunit as the planter is drawn through the field.

The row unit frame 20 operably supports a seed hopper 23 which may beadapted to receive seed from a bulk hopper (not shown), a seed meter 26and a seed tube 28 as well as a furrow opener assembly 30 and furrowclosing assembly 40. The furrow opening assembly 30 comprises a pair offurrow opener discs 32 and a pair of gauge wheels 34. The gauge wheels34 are pivotally secured to the row unit frame 20 by gauge wheel arms36. A coil spring 50 is disposed between the parallel arms 16,18 toprovide supplemental downforce to ensure that the furrow opener discs 32fully penetrate the soil to the desired depth as set by a depthadjusting member (not shown) and to provide soil compaction for properfurrow formation. Rather than a coil spring, supplemental downforce maybe provided by actuators or other suitable means such as disclosed inU.S. Pat. No. 6,389,999 to Duello, the entire disclosure of which ishereby incorporated herein by reference.

In operation, as the row unit 10 is lowered to the planting position,the opener discs 32 penetrate into the soil. At the same time, the soilforces the gauge wheels 34 to pivot upwardly until the gauge wheel arms36 abut or come into contact with the stop position previously set withthe furrow depth adjusting member (not shown) or until a static loadbalance is achieved between the vertical load of the row unit and thereaction of the soil. As the planter is drawn forwardly in the directionindicated by arrow 39, the furrow opener discs cut a V-shaped furrow 60into the soil while the gauge wheels 34 compact the soil to aid information of the V-shaped furrow. Individual seeds 62 from the seedhopper 23 are dispensed by the seed meter 26 into an upper opening inthe seed tube 28 in uniformly spaced increments. As seeds 62 fallthrough the seed tube 28, the seeds move downwardly and rearwardlybetween the furrow opener discs 32 and into the bottom of the V-shapedfurrow 60. The furrow 60 is then covered with soil and lightly compactedby the furrow closing assembly 40.

It should be appreciated that because seeds 62 fall freely through theseed tube 28 in the row unit 10 described above, the path of travel ofthe seeds and the velocity of the seeds at the exit of the seed tube arerelatively unconstrained. It would be preferable to constrain the pathof travel of seeds 62 in order to reduce errors in spacing betweenseeds; i.e., placing seeds in the field at non-uniform spacing.Additionally, it would be preferable to control the velocity of seeds 62such that the seeds have a decreased horizontal velocity relative to theground upon landing in the furrow 60.

A seed conveyor 100 is illustrated in FIG. 2A. The seed conveyor 100includes a belt 140 stretched around upper and lower pulleys 152,154 andpreferably driven by the upper pulley 152; in other embodiments the seedconveyor may be driven by the lower pulley 154. The belt 140 includesflights 142. The seed conveyor 100 additionally includes a guide surface110 disposed adjacent to the flights 142 on one side of the seedconveyor. The seed conveyor 100 preferably includes a backing plate 130disposed to maintain the position of belt 140.

In operation, the seed conveyor 100 receives seeds 62 from a seed disc50 and conveys them to an exit 164. The seed disc 50 is preferablyhoused in a seed meter 26 similar to that illustrated in FIG. 1 androtates in a direction indicated by arrow 56 about a shaft 54 rotatablymounted in the seed meter. Turning to FIG. 2B, the seed meter 26 ispreferably of the vacuum type as is known in the art, such that a vacuumsource (not shown) creates a vacuum behind the seed disc 50 (on theperspective of FIG. 2B), thus creating a pressure differential acrossapertures 52 in the disc. As the apertures 52 rotate past a pool ofseeds in the location generally indicated by reference numeral 58, thepressure differential causes individual seeds 62 to become entrained oneach aperture 52 such that the seeds are carried by the disc asillustrated. As the apertures cross a boundary such as axis 196,preferably at approximately the 3 o'clock position of the seed disc 50,the vacuum source is substantially cut off (e.g., by termination of avacuum seal as is known in the art) such that the seeds 62 are releasedfrom the disc as they cross axis 196. Seeds 62 preferably fall from thedisc in a substantially vertical fashion along an axis 192. Guidesurface 110 includes an angled portion 112, along which each seed 62slides downward and rearward before passing between two flights 142 at aseed inlet generally indicated by reference numeral 162. Each seed 62 isthen conveyed downward by seed conveyor 100.

The belt 142 is preferably driven at a speed proportional to thegroundspeed St (FIG. 2C) of the row unit 10. For example, in someembodiments the seed conveyor 100 is driven such that the linear speedof belt 142 at the bottom of the lower pulley 154 is approximately equalto the groundspeed St.

As illustrated in FIG. 2B, each seed 62 is initially accelerateddownward by the flight 142 above the seed. Turning to FIG. 2C, as eachseed 62 moves downward along the seed conveyor 100, it may fall awayfrom the flight 142 above it. However, as each seed 62 nears the bottomof the seed conveyor, the flights 142 accelerate in order to travelaround lower pulley 154 such that the flights 142 contact the seed andimpart a rearward horizontal velocity to the seed. Additionally, anangled portion 114 of the guide surface 110 guides the seed rearward,imparting a rearward horizontal velocity to the seed. Thus, as the seed62 exits the seed conveyor at a seed exit generally indicated byreference numeral 164, the seed has a downward vertical velocitycomponent Vy and a horizontal velocity component Vx, the magnitude ofwhich is less than the speed of travel St of the row unit 10. It shouldbe appreciated that a smaller horizontal velocity component Vx ispreferable because the seed 62 will experience less fore-aft roll as itlands in the furrow 60, leading to more uniform seed placement. Theangled portion 114 preferably is disposed 20 degrees below horizontal.

Returning to FIG. 2B, it should be appreciated that flights 142 travelfaster as they travel around the upper end of upper pulley 152, e.g.,above an axis 194. Additionally, the flights 142 have a substantialhorizontal velocity component above axis 194. As a result, attempting tointroduce seeds 62 between the flights above axis 194 may result inseeds being knocked away from the belt 140. Thus, the seed inlet 162 atwhich seeds 62 pass between flights 142 is preferably below the axis194. This result is preferably accomplished by positioning of the axis196 at which seeds are released from the disc 50 below the axis 194and/or by configuring angled portion 112 of guide surface such thatseeds 62 slide below axis 194 before entering the inlet 162.

Turning to the embodiment of FIGS. 11A-11E, a seed conveyor 100 isillustrated in cooperation with a row unit 10. The row unit 10 includesa shank portion 35. Referring to FIG. 11A, the seed conveyor 100 ismounted to the shank portion 35 by attachment ears 106,108. Turning toFIG. 11B, the seed conveyor 100 includes sidewalls 82,84. A conveyormotor assembly 1022 is mounted to the sidewall 82. The conveyor motorassembly includes a conveyor motor 1020. The conveyor motor drives anoutput shaft 1026. The output shaft 1026 preferably drives the inputshaft 1024; in some embodiments the output shaft is coupled to an inputshaft by a drive belt (not shown), while in other embodiments the outputshaft and input shaft may be operably coupled by one or more gears. Theinput shaft 1024 is operably coupled to the upper pulley 152 of the seedconveyor 100. Turning to FIG. 11C, the seed conveyor is shown with guidesurface 110 removed for clarity, revealing the flights 142. Turning toFIG. 11D, the seed conveyor 100 is preferably disposed transverselyadjacent the seed disc 50. Turning to FIG. 11E, the seed conveyor 100 isdisposed to receive seeds 62 released from the seed disc 50 onto theangled portion 112 of the seed guide 110 (FIG. 11B). In operation, seeds62 are released from the surface of the seed disc 50 at approximatelythe three o'clock position. Seeds 62 slide along the angled portion 112of the seed guide 110 between the flights 142 of the belt 140.

As illustrated FIG. 2D, the orientation of the seed conveyor 100 withrespect to the seed meter 50 may be varied. In the embodiment of FIG.2D, the orientation of the seed conveyor 100 has been reversed from thatillustrated in FIG. 2A, reducing the space claim of the combination. Insuch alternative embodiments, seeds are preferably discharged from theseed conveyor 100 in a direction opposite to the direction of travel 39.Additionally, the seed conveyor 100 is preferably positioned to receiveseeds from the seed meter 50.

In the embodiment of FIG. 2E, the seed conveyor includes anunconstrained belt region 147. The unconstrained belt region 147 ispreferably located adjacent the seed guide 110. The unconstrained beltregion 147 is preferably located between the seed inlet 162 and the seedexit 164. As the belt 140 travels through the unconstrained belt region147, the belt is free to undergo small fore-aft deflections (to theright and left on the perspective of FIG. 2E). It should be appreciatedthat in the embodiment of FIG. 2E, the backing plate is preferablyomitted or located at a predetermined aft (rightward on the perspectiveof FIG. 2E) distance from the seed guide 110 to allow the belt 140 toundergo fore-aft deflections.

In an alternative embodiment illustrated in FIG. 3, a modified seedconveyor 200 includes a belt 240 having modified flights 242 havingbevels 244. As the belt 240 moves past a seed inlet 262, seeds 62 aremore easily introduced between the flights 242 because a larger verticalgap exists between flights at the seed inlet due to the bevels 244.Similar to the embodiment of FIGS. 2A-2C, a gap 118 between the guidesurface and the belt is preferably of a predetermined size large enoughto allow consistent clearance between the guide surface and the belt,but small enough to prevent seeds 62 from escaping from between flights.

In an alternative embodiment illustrated in FIG. 4A-4B, a modified seedconveyor 300 includes a modified belt 340 without flights. Referring toFIG. 4A, the belt 340 is disposed adjacent a modified guide surface 310.Backing plates 330,332 preferably retain the desired position of thebelt 340. Turning to FIG. 4B, the belt 340 preferably includes roughnesselements 344 such that the outer surface of the belt has a relativelyhigh effective coefficient of friction. Guide surface 310 includes aninner face 314 which is smooth (i.e., has a relatively low coefficientof friction) and is preferably substantially free from burrs, warping,and other surface imperfections. Thus, as seeds 62 are released from theseed disc 50 and into a modified seed inlet generally indicated byreference numeral 362, the seeds are drawn between the belt 340 and theguide surface and held static with respect to the belt while slidingdownward along the guide surface 314.

In some embodiments, the seed conveyor 300 of FIGS. 4A-4B is modified asillustrated in FIG. 4C. The modified seed conveyor 300′ includes amodified guide surface 310′ having an angled portion 312′. In apreferred embodiment, the conveyor 300′ is disposed with respect to theseed disc 50 such that angled portion 312′ is adjacent to the axis 196at which seeds 62 are released from the disc 50 (by vacuum cut-off asdiscussed elsewhere herein). Thus as each seed 62 is released from thedisc 50, the seed is pulled between the angled portion 312′ and the belt340. The belt 340 then continues to draw the seed 62 downward against asmooth interior face of the guide surface 310′ and discharged as in theembodiment of FIGS. 4A-4B. Thus the guide surface 310′ cooperates withthe belt 340 to pull seeds 62 from the disc 50 at approximately the sametime that each seed is released from the disc. In alternativeembodiments, the angled surface 312′ is disposed just above the axis 196such that the guide surface and belt begin to pull each seed from thedisc just before the seed is released from the disc. In otherembodiments, the angled surface 312′ may be disposed just below the axis196 such that the guide surface and belt catch each seed just after theseed is released from the disc. In still other embodiments, the seedconveyor 300′ may be located farther frontward or rearward (to the rightor left as viewed in FIG. 4C) such that seeds 62 are pushed from theapertures 52 by contact with either the belt 340 or with the angledsurface 312′.

Seed Sensing

As described further herein, the seed conveyor embodiments describedabove are preferably provided with seed sensors for detecting the timeat which each seed 62 passes known locations.

Turning to FIG. 5A, a bottom portion of a seed conveyor 400 similar tothe seed conveyor 100 of FIG. 2 is illustrated. The seed conveyor 400includes a guide surface 130 having an opening 490. A seed sensor 500 ismounted to guide surface 130. The seed sensor 500 may include an opticalsensor 510 disposed to detect light passing through a sensing region 495between the flights. It should be appreciated that the height ofmeasuring region 495 is less than or equal to the height of opening 490.The height of measuring region 495 is preferably greater than the heightof the flights and less than the gap between the flights. The opticalsensor 510 may additionally include a light source such as an LED forproviding light waves to be reflected by the belt for detection by thesensor. Alternatively, a separate light source (not shown) may bedisposed behind the belt (to the right in the perspective of FIG. 5A) soas to transmit light through apertures (not shown) in the belt towardsensor 510. In any case, the sensor 500 generates a signal which changesdue to the presence of a seed 62 in measuring region 495.

Turning to FIG. 5B, a central portion of a seed conveyor 450 similar tothe seed conveyor 400 is viewed from the front (from the left in theperspective of FIG. 5A), with the guide surface not shown for clarity.The seed conveyor 450 includes sidewalls 482,484 that cooperate with theguide surface to enclose the belt and flights 142. Sidewalls 482,484include openings 452,454 respectively, which openings are preferablyaligned along a horizontal axis. A seed sensor 550 includes atransmitter 520 mounted to sidewall 484 and a receiver 515 mounted tosidewall 482. In some embodiments, the seed sensor 550 is an opticalsensor. The transmitter 520 is disposed to transmit light throughaperture 454, through a sensing region 497, and through aperture 452.The receiver 515 is disposed to detect light transmitted through thesensing region 497 and aperture 452. The height of sensing region 497 ispreferably equal to the height of apertures 452,454. The height ofsensing region 497 is preferably greater than the height of flights 142and less than the vertical spacing between the flights. The depth (onthe perspective of FIG. 5B) of sensing region 497 is preferably the sameas the depth of flights 142. The sensor 550 generates a signal whichchanges due to the presence of a seed 62 in measuring region 497.

Turning to FIG. 5C, it should be appreciated in light of this disclosurethat in either of the seed conveyor embodiments 400,450, the verticallocation of the seed sensors 500,550 may be selected in order to selectthe location of each seed 62 relative to the flights 142 at the pointwhere the seed is detected.

In order to detect seeds while the seeds are positively constrainedagainst a flight 142, the seed sensor are preferably placed along anupper portion of the belt in a zone A (FIG. 5C). In zone A, each seed 62is in contact with the flight above the seed until the seed isaccelerated by gravity to a speed in excess of the belt speed. Toachieve a similar result, in other embodiments, the seed sensor isplaced in a zone C, in which the flights have accelerated and again pushthe seeds along the seed path.

Alternatively, in order to detect the seed when it is separated from theflights 142, the sensor is preferably located in a zone B. In zone B,the seed has been accelerated by gravity to a speed faster than the beltspeed and separated from the flight above it, but has not yet contactedthe flight below.

In other embodiments, the seed conveyor may incorporate anelectromagnetic seed sensor. In one such embodiment, referring to FIG.5D, a seed conveyor 150 includes a seed guide 187 incorporating anelectromagnetic seed sensor 800. In such embodiments, seeds 62 slidealong an inner face 164 of the seed guide 187, passing through a sensorarc 810 before exiting the seed conveyor 150. Turning to FIG. 5E, whichillustrates the electromagnetic seed sensor 800 along the section 5E-5Eof FIG. 5D, the sensor arc 810 houses an electromagnetic energytransmitter 822 and a receiver 824. A circuit board 830 and associatedcircuitry is housed in the seed guide 187. The circuit board 830 is inelectrical communication with the transmitter and receiver 822,824. Thetransmitter 822 generates electromagnetic energy which crosses a sensingregion 850 within the sensor arc 810. The detector 824 generates asignal related to a characteristic of the electromagnetic energyreceived from the transmitter 822. As each seed 62 passes through thesensing region 850, a characteristic of the electromagnetic energytransmitted to the detector 824 is modified such that the signalgenerated by the detector is likewise modified. The seed sensor 800 maybe substantially similar to any of the electromagnetic seed sensorsdisclosed in Applicant's U.S. patent application Ser. No. 12/984,263,the disclosure of which is hereby incorporated herein in its entirety byreference.

In other embodiments, turning to FIG. 5F, a similar electromagnetic seedsensor 800 is mounted to the angled portion 112 of the seed conveyor100. In such embodiments, seeds 62 pass through the sensor arc 810 afterbeing released from the seed meter 50 and before entering betweenflights 142 of the seed conveyor. It should be appreciated that invarious embodiments, the sensor arc 810 may be positioned such thatseeds 62 pass through the sensor arc either before or after contactingthe angled portion 112. In other embodiments, an optical sensor may bedisposed to sense the passage of seeds in the same location as thesensor arc 810 of FIG. 5F.

Turning to FIG. 6A, an additional seed sensor 600 may be used to detectthe presence of seeds 62 on the disk 50. The seed sensor 600 ispreferably disposed to detect passing seeds 62 on the surface of thedisc. The seed sensor 600 may comprise an optical transmitter 610configured to emit light to an optical receiver 620, which is preferablyconfigured to produce a signal related to the amount of light receivedfrom transmitter 610. The transmitter and receiver 610,620 arepreferably mounted to a seed meter housing 20 of the seed meter 26enclosing the seed disc 50. As illustrated in FIG. 6A, the transmitterand receiver 610,620 are preferably disposed below and above the seedpath, respectively, such that passing seeds cause a light interruptionand modify the signal produced by the receiver 620. Thus when a seed isnot present on an aperture 52 (e.g., aperture 52 a), the receiver 620produces a modified signal. It should be appreciated in light of thisdisclosure that where a seed stripper or singulator 22 is incorporatedin the seed meter 26 in order to remove excess seeds from apertures 52,such devices may occasionally “strip” an aperture such that no seed iscarried to the seed conveyor 100. Thus the seed sensor 600 is preferablydisposed downstream along the seed path with respect to the singulator22.

In other embodiments, as illustrated in FIGS. 6B and 6C, a transverseseed sensor 700 preferably comprises a transmitter 710 and receiver 720disposed to transmit and receive light across the apertures 52 in atransverse direction, such that light from transmitter 710 istransmitted to the receiver 720 if no seed is present on the aperture(e.g., aperture 52 a). In such an embodiment, the receiver 720 receiveslight and emits a modified signal when a “skip” (i.e., a failure to loador retain at least one seed on the disk) occurs.

A transverse seed sensor may also be incorporated in the seed conveyor300 of FIGS. 4A-4B. Referring to FIG. 7A, a seed sensor 900 isincorporated into a modified seed conveyor 350. The seed sensor 900 istransversely disposed to detect the passage of seeds through a sensingregion 997 between the belt 340 and an inner face 354 of the seedconveyor 350. Turning to FIG. 7B, the seed conveyor 350 includesspaced-apart transverse sidewalls 382,384. The sidewalls 382,384 includeapertures 352,354, respectively. A transmitter 910 is mounted tosidewall 382. Transmitter 910 is configured to transmit light (or otherelectromagnetic energy) through the aperture 352, through the sensingregion 997, and through the aperture 354. A receiver 920 is mounted tosidewall 384. Receiver 920 is configured to generate a signal whichchanges due to the presence of a seed in measuring region 997.

Loading Wheel Seed Conveyor Embodiments

Turning to FIGS. 12A-13, a seed conveyor 1200 including loading wheelsis illustrated. Referring to FIGS. 12A and 12B, the seed conveyor 1200includes a housing 1210 in which a first loading wheel 1202 and a secondloading wheel 1204 are rotatably supported by the meter housing 1210,preferably above the apex of the belt 140. The loading wheels arepreferably driven to rotate as described later herein; on the view ofFIG. 12A, loading wheel 1202 preferably rotates in the clockwisedirection and loading wheel 1204 preferably rotates in thecounter-clockwise direction. The loading wheels 1202,1204 are preferablyspaced to leave a gap 1201 between the loading wheels, preferably abovethe apex of the belt 140. The gap 1201 is preferably sized to permitseeds to pass through with a small amount of compression of each loadingwheel, such that a seed placed in the gap is positively constrained bythe loading wheels 1202,1204. The gap is preferably 0.01 inches wide forseed conveyors used to plant corn and soybeans. The loading wheel 1202preferably includes vanes 1207 and the loading wheel 1204 preferablyincludes vanes 1209. The loading wheels 1202,1204 are preferably made ofa material having relatively low compressibility. In some embodiments,the loading wheels 1202,1204 are made of polyurethane. It should beappreciated that the vanes in each loading wheel make the loading wheelmore compressible than a solid piece of relatively incompressiblematerial such that the loading wheels may be compressed to receive seedsin the gap 1201. In other embodiments each loading wheel is comprised ofa solid annular or cylindrical piece of a more compressible material;such embodiments are not preferred because more compressible materialstend to wear more quickly from repeated engagement of seeds. Asillustrated, the loading wheels 1202,1204 preferably include roughnesselements (e.g., ribbing) disposed substantially around the perimeters ofthe loading wheels.

Referring to FIG. 12C, the seed conveyor 1200 is illustrated incommunication with a seed disc 50 having a single radial array of seedapertures 52. The seed conveyor 1200 is preferably disposed adjacent theseed disc 50. In operation, as described elsewhere herein, the seedapertures pick up seeds 62 from a seed pool 58 located at approximatelythe six o'clock position on the view of FIG. 12C and are carried in aclockwise seed path. As the seeds 62 approach the housing 1210, theypreferably pass through a notch in a brush 1230 disposed to contact andclean the seed disc and then enter the housing 1210.

Referring to FIGS. 12C and 12E, seeds 62 preferably enter the housing1210 through a throat 1215 defined by a lower surface 1206 and an uppersurface 1211. The upper surface 1211 preferably comprises a lowersurface of an insert 1208 removably attached (e.g., by screws asillustrated herein) to the housing 1210. It should be appreciated thatthe upper surface 1211 is preferably part of a removable insert becausefrequent repeated contact with seeds 62 may cause appreciable weardepending on the material used to form the upper surface 1211. The uppersurface 1211 is preferably normal to the surface of the seed disc 50.The upper surface 1211 preferably includes a curvilinear portion 1281concentric with the seed apertures 52 and a subsequent curvilinearportion 1283 along which the upper surface 1211 curves continuously fromconcentricity with the seed apertures 52 to become approximatelytangential with the outer perimeter of the loading wheel 1202. Thesurface 1211 preferably terminates adjacent to the gap 1201. Turning toFIG. 12M, the seed apertures 52 define an outer radius Ro, a medianradius Rm and an inner radius Ri from the center of the seed disc 50.The curvilinear portions 1281 and 1283 preferably have radii between Roand Rm. The curvilinear portion 1283 preferably has a radius approachingRm toward the terminal end of the upper surface 1211. The lower surface1206 preferably has a radius less than Ri. In operation, each seed 62 ispreferably dislodged inwardly from the seed aperture 52 by contact withthe curvilinear portion 1281 but preferably remains entrained on theseed aperture while in contact with the curvilinear portion 1281. Theseed 62 is further dislodged inwardly from the seed aperture 52 bycontact with the curvilinear portion 1283.

Turning to FIG. 12D, the seed conveyor 1200 is illustrated incommunication with a seed disc 51 having an array of inner seedapertures 52 i arranged concentrically with an array of outer seedapertures 52 o. Those skilled in the art will recognize that such discsare conventionally used to plant soybeans and other crops. The seedconveyor 1200 is preferably configured to partially dislodge seeds fromboth aperture arrays and subsequently constrain or “pinch” them betweenthe loading wheels. For example, the loading wheel 1204 is disposed tointersect the path of the array of inner seed apertures 52 i such thatthe loading wheel 1204 urges seeds from the inner seed apertures towardthe gap 1201. As illustrated, the upper surface 1211 is preferablydisposed similarly with respect to the outer seed apertures 52 o asdescribed herein with respect to the apertures 52 in FIG. 12M.

Returning to FIG. 12C, after the seeds 62 pass the curvilinear portion1283, they enter the gap 1201 between the loading wheels 1202,1204. Theloading wheels 1202,1204 are slightly compressed by the introduction ofeach seed into the gap 1201 such that the wheels positively constrainthe seed in the gap. The vacuum seal imposing a vacuum on the apertures52 preferably terminates adjacent to the gap 1201 at an axis 196′ suchthat seeds 62 are released from the disc 50 just before entering thegap. Due to the rotation of the loading wheels, the seed 62 is thenejected downward toward the belt.

Returning to FIG. 12A, seeds 62 ejected by the loading wheels 1202,1204travel along a nominal seed path Ps which is tangential to both of theloading wheels. Seeds ejected by the loading wheels 1202,1204 preferablyfreefall along the seed path Ps under the influence of gravity and thevelocity imparted on the seeds by ejection from the loading wheels1202,1204. Seed traveling along seed path Ps preferably enters betweenflights of the belt 240 forward (to the left on the view of FIG. 12A) ofa plane Ad dividing the ascending and descending portions of the belt.Thus the seed path Ps intersects a descending portion of the belt 240.

Returning to FIG. 12C, seeds 62 enter the belt 52 between flights 242and pass by a surface 1225, which preferably comprises a surface of aninsert removably attachable (e.g., by screws as illustrated) to thehousing. The surface 1225 preferably includes agitation elements (e.g.,ribbing) sized to agitate seeds 62 which may occasionally beaccidentally trapped between the flight 242 and the inner wall of thehousing 1210 instead of being introduced between flights as desired;upon agitation against the surface 1225, the seeds are released frombeing trapped between the flight 242 and the inner wall of the housing1210 and pass in between adjacent flights. It should be appreciated thatallowing a seed 62 to remain trapped between the flight 242 and theinner wall of the housing 1210 causes unnecessary wear on the housing1210, damages the seed, damages the belt 240, and causes seed spacingerrors due to reflexive action of the flight upon release of seed fromthe conveyor 1200.

Turning to FIGS. 12I, 12J, 12K, and 12L, the seed conveyor 1200preferably includes a seed conveyor motor 1020. The seed conveyor motor1020 is preferably housed within a motor housing 1212 of the housing1210. The motor 1020 preferably drives the seed conveyor via a gearbox1250. The motor 1020 preferably also drives the loading wheels 1202,1204via the gearbox 1250.

Referring to FIG. 12J, the motor 1020 drives an output gear 1258. Theoutput gear preferably drives an idler gear 1257. The idler gear 1257preferably drives an idler gear 1253. The idler gear 1253 preferablydrives a conveyor input gear 1256. Thus the output gear 1258 indirectlydrives the conveyor drive gear 1256.

The conveyor input gear 1256 preferably drives an idler gear 1255. Theidler gear 1255 preferably drives a loading wheel drive gear 1254. Thusthe output gear 1258 indirectly drives the loading wheel drive gear1254.

The idler gear 1257 preferably drives a loading wheel drive gear 1252.Thus the output gear 1258 indirectly drives the loading wheel drive gear1252.

Turning to FIG. 12I, the loading wheel drive gear 1252 preferably drivesthe loading wheel 1202 via a shaft 1251-2. The loading wheel drive gear1254 preferably drives the loading wheel 1204 via a shaft 1251-4. Theconveyor drive gear 1256 preferably drives the upper pulley 152 via ashaft 1251-6.

The gears constituting the gearbox 1250 are preferably relatively sizedas illustrated in FIG. 12J. The gears constituting the gearbox 1250 arepreferably relatively sized such that the angular speeds of theperimeters of the loading wheels 1202,1204 are substantially equal. Thegears constituting the gearbox 1250 are preferably relatively sized suchthat a ratio between the linear speed of the perimeter of the loadingwheel 1204 and the linear speed of the outer perimeter of flights 242 onthe descending portion of the belt 240 is approximately 0.73. In otherembodiments, the gears constituting the gearbox 1250 are relativelysized such that a ratio between the linear speed of the perimeter of theloading wheel 1204 and the linear speed of the outer perimeter offlights 242 rounding the top belt 240 is approximately 0.73.

Referring to FIGS. 12I and 12K, the gearbox 1250 is preferably enclosedby a cover 1249 securing a seal 1259 against the meter 26.

In other embodiments, the seed disc 50 is also indirectly driven by themotor 1020, e.g., by a drive belt connecting a gear driven by outputgear 1258 to a shaft on which the seed disc is mounted for rotation. Instill other embodiments, the loading wheels 1202,1204 are driven by aseparate motor from the motor 1020. As illustrated, the seed disc 50 ispreferably driven by a separate meter drive motor 27 which preferablycomprises an electric motor disposed to drive gear teeth provided on theperimeter of the seed disc 50 as disclosed in Applicant's co-pendingU.S. application Ser. No. 61/675,714, the disclosure of which is herebyincorporated herein in its entirety by reference.

Turning to FIGS. 12F, 12G, and 12H, the seed conveyor 1200 isillustrated from top to bottom. As with the other seed conveyorembodiments described elsewhere herein, the belt 240 conveys seeds 62downwardly toward a seed exit 164 at which an angled portion 114 importsa rearward horizontal velocity to the seeds as the seeds are releasedsequentially into the trench.

Turning to FIG. 12G, 12H, and 12K, the seed conveyor 1200 preferablyincludes a housing portion 1232 and a housing portion 1234 whichcooperate to enclose the belt 240 during operation. The housing portions1232,1234 preferably comprise three walls each. Referring to FIG. 12K,the housing portion 1232 preferably engages the housing 1234 such thattwo fore-aft walls of the housing portion 1232 are received within twofore-aft walls of the housing portion 1234.

To assemble the seed conveyor 1200, the user first attaches the housingportion 1232 to the housing 1210 using attachment ears 1233. Referringto FIG. 12K, the user then slides the housing portion 1234 over thehousing portion 1232 in a transverse direction and then slides thehousing portion 1234 downwardly such that attachment ears 1235 in thehousing portion 1234 engage protrusions 29 in the housing 1210. When thehousing portions 1232,1234 are relatively positioned such that theattachment ears 1235 engage protrusions 29, a spring 1236 mounted to thehousing portion 1234 is allowed to relax such that a portion of thespring extends through openings in the housing portions 1232,1234, thusretaining the relative vertical position of the housing portions1232,1234. To disassemble the seed conveyor 1200, the user first pullsback the spring 1236 to allow the housing portions 1232,1234 to slidevertically relative to one another, then slides the housing portion 1234upwards and then away from the housing portion 1232.

Turning to FIG. 15, process 1500 for planting seeds using the seedconveyor 1200 is illustrated. At step 1505, the seed disc 50 ispreferably rotated through the seed pool and a seed is preferablycaptured by the seed meter. In the implementation of process 1500 usinga vacuum-type seed meter or positive air seed meter, the step ofcapturing seeds is accomplished by entraining seeds onto the seedapertures 52 of a seed disc 50. In the implementation of process 1500using a finger pickup-style meters such as those disclosed in U.S. Pat.No. 6,273,010, the entire disclosure of which is hereby incorporatedherein by reference, the step of capturing a seed is accomplished bycapturing each seed with a spring-loaded mechanical finger. At step1510, the loading wheels 1202,1204 are preferably driven to rotate inopposite directions. At step 1515, the seed conveyor 1200 is driven suchthat flights 142 circulate around the belt 240. At step 1520, a seed isreleased (e.g., from an aperture 52 of the seed disc 50), preferablyadjacent to the loading wheels 1202,1204 and preferably above theloading wheels 1202,1204. At step 1525, the seed is preferably capturedbetween the loading wheels 1202,1204. At step 1525, one of the loadingwheels is preferably deformed to receive the seed in the gap 1201. Atstep 1530, the seed is preferably ejected from between the loadingwheels 1202,1204. At step 1530, one of the loading wheels preferablyreturns to a relaxed state. At step 1530, the seed is preferably ejecteddownward into the belt 240, i.e., between flights 142. At step 1535, theseed is conveyed to a lower end of the belt 240 between flights 142. Atstep 1540, the seed is released from the belt with a rearward horizontalvelocity, e.g., by releasing the seed along surface 114.

Turning to FIG. 13, the seed conveyor 1200 is illustrated mounted to arow unit 1300. The row unit 1300 preferably includes a closing wheelattachment portion 1302 for pivotally mounting a closing wheel assembly(not shown) to the row unit and parallel arm attachment apertures 1320for pivotally mounting a parallel arm arrangement (not shown) to the rowunit. The parallel arm arrangement is pivotally mounted to a toolbar(not shown) such that the row unit 1300 is allowed to translatevertically with respect to the toolbar as the row unit traverses afield. The row unit 1300 preferably includes two transversely spacedsidewalls 1304, preferably located below the mounting location of themeter 26. The row unit 1300 preferably includes a downwardly extendingshank 1306 having a pair of opener disc axles 1310 for pivotallymounting a pair of opener discs to either side of the shank 1306. Abracket 1340 is preferably mounted to a lower portion of the shank 1306.The bracket 1340 preferably includes two transversely spaced sidewalls1342 extending rearwardly and joined at a rearward end of the bracket1340. A seed firmer 1307 is preferably mounted to the rearward end ofthe bracket 1340. The seed firmer 1307 is preferably disposed toresiliently contact the bottom of the trench (not shown) opened by the.The seed firmer 1307 is preferably made of a resilient material. In someembodiments, the seed firmer 1307 comprises seed firmers such as thosedescribed in U.S. Pat. No. 5,425,318, the disclosure of which is herebyincorporated in its entirety herein by reference.

The user preferably mounts the seed conveyor 1200 to the row unit 1300by extending the seed conveyor between the sidewalls 1304 of the rowunit and the sidewalls 1342 of the bracket 1340. The seed conveyor 1200is preferably mounted to the row unit 1300 via structure (not shown)adjacent the sidewalls 1304. Referring to FIGS. 12F, 12G and 12H, theseed conveyor 1200 preferably includes two transversely extendingspacers 1248 which contact interior surfaces of the sidewalls 1342 ofthe bracket 1340, maintaining a lower end of the seed conveyor insubstantial alignment with the trench opened by the opening discs and insubstantial alignment with the seed firmer 1307.

The seed conveyor 1200 preferably includes a seed sensor 550 comprisedof a transmitter 520 mounted to the housing portion 1232 and a receiver515 mounted to the housing portion 1234. The housing portions 1232,1234preferably include openings (not shown) aligned along a transverselyextending axis such that light (or other signals) transmitted by thetransmitter 520 pass through the openings and between flights of thebelt 240 to the receiver 515.

Turning to FIG. 14, a seed conveyor 1400 having a single loading wheel1420 is illustrated. The seed conveyor 1400 is preferably disposed suchthat the path of seed apertures 52 intersects the descending portion ofthe belt 140. The vacuum imposed on the seed apertures 52 is preferablysubstantially cut off (e.g., by the terminal end of a vacuum seal)adjacent to a plane Pv intersecting the location at which seeds enterthe belt 140. Thus seeds are released from the disc just prior toentering the belt (i.e., passing between flights 142 of flight). Theloading wheel 1420 is preferably located adjacent to the location atwhich seed enter the belt 140. The loading wheel 1420 is preferablydriven for rotation about a central axis in the direction indicated bythe arrow in FIG. 14. The surface of the loading wheel thus urges theseeds into the belt and prevents seeds from being stuck between the tipsof flights 142 and a wall 1430 adjacent to the belt 142. The surface ofthe loading wheel 1420 preferably includes roughness elements asillustrated in FIG. 14 such that the loading wheel exerts greaterfrictional forces on the passing seeds. A guide 1410 preferably guidesseeds into contact with the loading wheel 1420.

Conveyor Control Systems and Methods

A control system 1000 for controlling and monitoring the seed conveyor100 as well as any other seed conveyor embodiment disclosed herein isillustrated schematically in FIG. 8A. The control system 1000 includes aplanter monitor 1005. The planter monitor 1005 preferably includes a CPUand user interface, and may comprise a monitor such as that disclosed inApplicant's co-pending U.S. patent application Ser. No. 12/522,252. Theplanter monitor 1005 is preferably in electrical communication with aseed conveyor motor 1020. The seed conveyor motor 1020 is operablycoupled to the seed conveyor 100 to drive the seed conveyor. Forexample, in some embodiments the seed conveyor motor 1020 includes adriven output shaft mechanically coupled to a central shaft of the upperpulley 154 or the lower pulley 152. The seed conveyor 1020 preferablyincludes an encoder (e.g., a hall-effect sensor) for sensing therotational speed of the conveyor 100. The planter monitor 1005 ispreferably in electrical communication with a meter drive motor 27. Themeter drive motor 27 may comprise any apparatus known in the art fordriving seed meters at a desired speed such as a hydraulic drive orelectric drive. As an example, the meter drive motor 27 may comprise anelectric motor mounted on or near the seed meter 50, the electric motorhaving an output shaft operably coupled to the shaft 54 of the seedmeter; in such an embodiment, the meter drive motor 27 preferablyincludes an encoder (e.g., a hall-effect sensor) for sensing therotational speed of meter 50. In other embodiments, the meter drivemotor 27 may comprise a ground drive driven by the rotation of planterwheels 8 (FIG. 9B). The planter monitor 1005 is also preferably inelectrical communication with a speed source 1010. The speed source maycomprise a GPS system, a radar speed sensor, or a wheel speed sensor.The planter monitor may choose between multiple speed sources bypredicting reliability as disclosed in Applicant's co-pending PCT PatentApplication No. PCT/US2011/045587, incorporated herein in its entiretyby reference.

Continuing to refer to FIG. 8A, the planter monitor is preferably inelectrical communication with one or more seed sensors adapted formounting to the seed conveyor 100. The seed sensors may comprise one ormore of the seed sensors 500,550,700,800,900 described herein. The seedsensors may also be in electrical communication with the meter drivemotor 27 and the seed conveyor motor 1020.

Turning to FIG. 8B, one embodiment of a planter monitor control system1000 is illustrated. The planter monitor control system 1000 of FIG. 8Bincludes a seed sensor 550 mounted to the sidewalls of the seed conveyor100. The meter drive motor 27 in the planter monitor control system 1000of FIG. 8B comprises an electric drive. The speed St of seed conveyor100 is generally to the left along the perspective of FIG. 8B and has amagnitude which varies with the speed and direction of the plantingimplement.

A process 1100 for controlling the rotational speed of the seed conveyor100 is illustrated in FIG. 9A. At block 1102 the planter monitor 1005obtains a speed of the planting implement from the speed source 1010. Atblock 1103, the planter monitor 1005 preferably obtains the currentcommanded planting population (i.e., the number of desired seeds plantedper acre) from a memory contained within the planter monitor 1005. Atblock 1105, the planter monitor 1005 preferably commands a rotationalspeed of meter 50 based on the desired population and the currentimplement speed.

Continuing to refer to FIG. 9A, at block 1110, the planter monitor 1005preferably determines an operating speed of the seed conveyor 100. Thisstep may be accomplished using a Hall-effect or other sensor adapted tomeasure the driving speed of the electric motor or the rotational speedof the driven shaft of the seed conveyor 100. This step may also beaccomplished by measuring the time between flights 142 passing the seedsensor 550. It should be appreciated in light of the instant disclosurethat step of block 1110 does not require measuring an actual operationalspeed but may comprise measuring a criterion related to the operationalspeed.

Continuing to refer to FIG. 9A, at block 1500 the planter monitor 1005preferably determines the ground speed St of the seed conveyor 100. Insome embodiments, this step may be accomplished by assuming that thetractor or implement speed reported by the speed source 1010 is equal tothe ground speed St of the seed conveyor 100. Such a method is accuratewhen the tractor and toolbar 12 are not turning, but becomes inaccuratewhen the tractor and toolbar 12 are turning. In other embodiments thestep of block 1500 may be performed more accurately by determining thelocal ground speed St of each conveyor 100 along the toolbar 12. Suchembodiments are described herein in the section entitled “ConveyorGround Speed Determination.”

Returning to FIG. 9A and process 1100, at block 1117 the planter monitor1005 preferably determines a conveyor motor speed command using acalibration curve. A preferred calibration curve 990 is illustrated inFIG. 9E. The calibration curve 1200 relates the ground speed St to adesired operational speed So. It should be appreciated in light of theinstant disclosure that the calibration curve 990 could also relate acriterion related to ground speed (such as a measured voltage orcommanded voltage) to a criterion related to a desired conveyor speed(such as a measured voltage or commanded voltage). The calibration curve990 preferably includes a sloped portion 992 (e.g., having a slopeapproximately equal to 1) in which operational speed is directly relatedto ground speed. The calibration curve 990 preferably includes azero-slope portion 991 in which operational speed does not decrease asthe ground speed decreases. The constant portion 991 is preferably belowa minimum ground speed St-1 (e.g., 1 mile per hour). A slope of thecalibration curve 990 preferably changes below the minimum ground speedSt-1. The calibration curve 990 preferably has a non-zero minimumoperational speed So-1 (e.g., 100 rpm at the upper pulley 152). Itshould be appreciated in light of the instant disclosure that azero-slope portion is not required to ensure a non-zero minimumoperational speed. It should also be appreciated in light of the instantdisclosure that a non-zero minimum operational speed is preferable inorder to simplify control of the seed conveyor when stopping andstarting the planting implement. The minimum operational speed So-1 ispreferably small enough that seeds 62 exiting the seed conveyor 100 donot have sufficient rearward horizontal velocity Vx (FIG. 2C) to causesubstantial seed bounce or roll at low ground speeds (e.g., less than 1mile per hour).

Returning to FIG. 9A and the process 1100, at block 1120 the plantermonitor 1005 preferably commands the new desired conveyor speed. Itshould be appreciated in light of the instant disclosure that the changein conveyor speed command may be deferred until the actual conveyorspeed is outside of a preferred range, e.g. 5%, with respect to thedesired conveyor speed.

Turning to FIG. 10A, a process 1600 is illustrated for shutting off andturning on the seed conveyor 100 at planting boundaries. Turning to FIG.10B, the seed conveyor is illustrated at three locations indicated by100, 100′, and 100″ along direction of travel 39. As illustrated, themeter 50 has introduced several seeds 62 into the seed conveyor 100; theearliest seed introduced into the seed conveyor 1200 is identified asseed 62-1. The seed conveyor 100 first crosses a first planting boundary1710, thus entering into a no-planting region 1715 (e.g., a waterway),and then crosses a second planting boundary 1720, thus exiting theno-planting region 1715. In overview, the process 1600 shuts off theseed conveyor 100 at the first planting boundary 1710, advances theearliest seed 62-1 a distance De to the exit while the conveyor is inthe no-planting region, and starts the seed conveyor at the secondplanting boundary 1720.

Returning to FIG. 10A to describe the process 1600 in detail, at block1610 the planter monitor 1005 preferably determines whether the seedconveyor is within a predetermined distance or time from crossing aplanting boundary. The current distance to a planting boundary ispreferably estimated by comparing the position reported by a GPSreceiver 5 (FIG. 9B) to the position at which a planting boundaryintersects a line along the direction of travel. The time to a plantingboundary is preferably estimated by dividing the distance to a plantingboundary by the speed currently reported by the speed source 1010. Oncethe seed conveyor 100 is within a predetermined time or distance of aplanting boundary, at block 1615 the planter monitor 1005 preferablybegins to record the distance De between the earliest seed 62-1 in theseed conveyor and the seed exit 164. The distance De is preferablyrecorded by recording the time of each seed pulse from the seed sensor550 (FIG. 8B) and then estimating the position of the seed byintegrating the speed of the conveyor motor 1020. When De equals zero,it is assumed that the earliest seed 62-1 in the conveyor has exited theconveyor and the planter monitor 1005 preferably identifies the nextearliest seed as the earliest seed 62-1. At block 1620, the plantermonitor 1005 determines whether the seed conveyor 100 has crossed aplanting boundary (e.g., planting boundary 1710 in FIG. 10B). Once theconveyor has crossed a planting boundary into a no-planting region(e.g., no-planting region 1715 in FIG. 10B), at block 1625 the plantermonitor 1005 commands the meter drive motor 27 (FIG. 8B) to shut off oralternatively commands a clutch associated with the seed meter 50 todisengage. At block 1628, the planter monitor 1005 preferably allows apredetermined delay to pass before commanding the conveyor motor 1020 tostop at block 1630. The predetermined delay may vary with ground speedand planting population and may be based on empirically determineddelays between meter stop commands and the last seed deposited by themeter 50 into the seed conveyor 100.

Continuing to refer to FIG. 10A, at block 1635 the planter monitor 1635preferably advances the seed conveyor 100 such that the belt 140 travelsthrough a distance De, thus moving the last seed 62-1 adjacent to theseed exit 164. At block 1640, the planter monitor 1005 preferablydetermines whether the seed conveyor 100 has crossed a planting boundary(e.g., planting boundary 1720 in FIG. 10B). Once a planting boundary hasbeen crossed, the planter monitor 1005 preferably starts the conveyormotor 1020 at block 1645 and preferably subsequently starts the meterdrive motor 27 (or alternatively commands a clutch associated with themeter 50 to engage) at block 1650.

Turning to FIG. 10C, another process 1600′ is illustrated for shuttingoff and turning on the seed conveyor 100 at planting boundaries. Turningto FIG. 10D, the seed conveyor is illustrated at three locationsindicated by 100, 100′, and 100″ along direction of travel 39. As withprocess 1600, process 1600′ shuts off the seed conveyor 100 at the firstplanting boundary 1710, advances the earliest seed 62-1 to the seed exitwhile the conveyor is in the no-planting boundary, and starts the seedconveyor at the second planting boundary 1720. However, rather thancalculating and storing the distance De as in process 1600, process1600′ uses a seed sensor 1800 to determine the location of the earliestseed 62-1. The seed sensor 1800 is preferably be an optical seed sensormounted to the seed conveyor 100 in a fashion similar to the seed sensor550 described herein. The seed sensor 1800 is preferably disposed tosense seeds 62 adjacent the seed exit. The seed sensor 1800 ispreferably disposed to sense seeds 62 prior to release; i.e., before theflight 142 below the seed is sufficiently separated from seed guide 110to allow the seed to exit the seed conveyor 100.

Returning to FIG. 10C to describe the process 1600′ in detail, at block1620 the planter monitor 1005 preferably determines whether the seedconveyor 100 is at a planting boundary (e.g., first planting boundary1710 in FIG. 10D). Once the conveyor has crossed a planting boundaryinto a no-plant region (e.g., no-plant region 1715 in FIG. 10D), atblock 1625 the planter monitor 1005 commands the meter drive motor 27(FIG. 8B) to shut off or alternatively commands a clutch associated withthe seed meter 50 to disengage. At block 1632, the planter monitor 1005preferably commands the conveyor motor 1020 to advance. Once a seedpulse has been received from seed sensor 1800, the planter monitor 1005preferably commands the conveyor motor 1020 to stop at block 1637. Atblock 1640, the planter monitor 1005 preferably determines whether theseed conveyor 100 has crossed a planting boundary (e.g., plantingboundary 1720 in FIG. 10B). Once a planting boundary has been crossed,the planter monitor 1005 preferably starts the conveyor motor 1020 atblock 1645 and preferably subsequently starts the meter drive motor 27(or alternatively commands a clutch associated with the meter 50 toengage) at block 1650.

Conveyor Ground Speed Determination

As noted elsewhere herein, in order to match the operating speed of theseed conveyor 100 to the ground speed St of the conveyor, it isdesirable to determine the ground speed of each seed conveyor at eachrow unit 10. This determination becomes more complex when the implementis turning, because the speed of each seed conveyor 100 varies accordingto its distance from the center of the turn. Thus several alternativesystems and methods of determining individual conveyor ground speed Stare disclosed herein.

Conveyor Ground Speed Determination—Systems

Turning to FIG. 9B, the toolbar 12 is drawn through the field by atractor 2. The toolbar 12 is preferably mounted to the tractor 2 by ahitch 13 near the transverse center of the toolbar. Toolbar 12 issupported by wheels 8, which are mounted in transversely spaced relationalong the toolbar. A right wheel 8-1 is mounted at a transverse distanceDw-1 from the center of the toolbar 12. A left wheel 8-2 is mounted at atransverse distance Dw-2 from the center of the toolbar 12. Wheels 8 maybe mounted to the toolbar 12 in a fashion similar to the wheel and tireassemblies disclosed in U.S. patent application Ser. No. 12/270,317(Pub. No. US 2010/0116974). Row units 10, each preferably including aseed conveyor 100, are mounted in transversely spaced relation along thetoolbar 12. A right row unit 10-1 is located at a transverse distance D1from the center of toolbar 12. A left row unit 10-2 is located at atransverse distance D2 from the center of toolbar 12.

Continuing to refer to FIG. 9B, several data-gathering devices arepreferably mounted to the tractor 2 and the toolbar 12. A gyroscope 6 ispreferably mounted to the toolbar 12. The gyroscope 6 is preferably inelectrical communication with the planter monitor 1005. A three-axisaccelerometer 7 is preferably mounted to the toolbar 12. Theaccelerometer 7 is preferably mounted to the toolbar 12. The gyroscopeand accelerometer 6,7 are mounted to the toolbar at a transversedistance Da from the center of the toolbar 12. A GPS receiver 5 ispreferably mounted to the tractor 2. The GPS receiver 5 is preferably inelectrical communication with the planter monitor 1005. A radar speedsensor 11 is preferably mounted to the underside of the tractor 2. Theradar speed sensor 11 is preferably in electrical communication with theplanter monitor 1005. Wheel speed sensors 9 are preferably mounted towheels 8 and configured to measure the rotational speed of wheels 8.Wheel speed sensors 9 are preferably in electrical communication withthe planter monitor 1005. Wheel speed sensors 9 may be similar to therotation sensors described in U.S. patent application Ser. No.12/270,317 (Pub. No. US 2010/0116974). In other embodiments, a GPSreceiver and radar speed sensor are mounted to the toolbar 12.

Continuing to refer to FIG. 9B, while traveling through the field, thetractor 2 has a velocity Vt, while the right and left row units10-1,10-2 have velocities V1,V2 respectively. It should be appreciatedthat the ground speed St of each seed conveyor 100 is equal to the speedcomponent of the associated row unit velocity; e.g., the magnitude of V1is equal to the ground speed St of the seed conveyor associated with rowunit 10-1. Additionally, wheels 8-1,8-2 travel at longitudinal speedsSw1, Sw2. As illustrated in FIG. 9B, when the tractor 2 is traveling ina consistent direction (i.e., not turning), velocities Vt, V1 and V2 areequal. As illustrated in FIG. 9C, as the tractor 2 turns, the directionof velocity Vt changes and the velocities V1 and V2. The toolbar 12 hasan angular velocity w about a center of rotation C. The center ofrotation C is a distance Rc from the center of the toolbar 12. It shouldbe appreciated that the longitudinal speed of each point along thetoolbar 12 increases with the distance of each point from the center ofthe toolbar.

Conveyor Ground Speed Determination—Methods

Turning to FIG. 9D, process 1500 includes multiple methods ofdetermining conveyor ground speed St. It should be appreciated thatprocess 1500 of FIG. 9D is a detailed illustration of the block 1500 ofFIG. 9A.

At block 1506, the planter monitor 1005 preferably obtains the geometryrelevant to the available groundspeed determination method, e.g.,distances D1, D2, Da, Dw1, Dw2, the transverse and longitudinal offsetsbetween the GPS receiver 5 and the hitch 13, and the longitudinal offsetbetween the hitch 13 and the center of the toolbar 12. To accomplishthis step, the planter monitor 1005 preferably prompts the user to enterthe relevant distances and offsets via a series of graphical userinterface screens similar to those disclosed in Applicant's co-pendingPCT Patent Application No. PCT/US2011/045587, previously incorporatedherein by reference.

At block 1508, the planter monitor 1005 preferably selects the desiredmethod of ground speed St. In some embodiments step may be accomplishedby simply choosing the only available method. In other embodiments, themethod may be selected based on the stability of the signals used incertain methods (e.g., a method other than GPS may be selected duringperiods of GPS signal instability).

Turning first to the wheel speed method, at block 1520 the plantermonitor 1005 preferably determines the longitudinal speeds Sw1,Sw2 ofwheels 8-1,8-2 from the signals generated by wheel speed sensors9-1,9-2, respectively. At block 1522, the planter monitor 1005preferably determines the angular speed w of the toolbar 12 by arelation such as:

$w = \frac{S_{w\; 1} - S_{w\; 2}}{D_{w\; 1} + D_{w\; 2}}$

At block 1524, the planter monitor 1004 preferably determines thelongitudinal speed at a row unit, e.g., row unit 10-1, using a relationsuch as:

V ₁ =S _(w1) +w(D ₁ −D _(w1))

In this and each of the following methods described herein, the plantermonitor 1005 preferably stores the speed Vn of each row unit 10-n as thegroundspeed St of the seed conveyor 100 associated with the row unit10-n.

Turning next to the gyroscope method, at block 1530 the planter monitor1005 preferably determines the angular speed w of the toolbar 12 fromthe signal generated by the gyroscope 6. At block 1532, the plantermonitor 1005 preferably determines the longitudinal speed of onelocation along toolbar 12. In some embodiments, the longitudinal speedof the center of the toolbar 12 may be determined from the signalgenerated by the radar speed sensor 11. In other embodiments, thelongitudinal speed of the accelerometer 7 may be determined byintegrating the signal from the accelerometer. At block 1534, theplanter monitor 1005 preferably calculates the velocity of, e.g., therow unit 10-1 based on the angular speed w and the known longitudinalspeed of a location on the toolbar. Assuming theaccelerometer-integrated speed (Sa) is used, the planter monitor 1005preferably uses a relation such as:

V ₁ =S _(a) +w(D ₁ −D _(a))

Turning next to the GPS method, at block 1510 the planter monitor 1005preferably records the GPS position over a period of time. At block1514, the planter monitor 1005 preferably determines the distance Rcfrom the center of the toolbar 12 to the center of rotation of thetoolbar. At block 1516, the planter monitor 1005 preferably determinesthe longitudinal speed of the center of the toolbar (Vc) from thetractor speed Vt reported by the radar speed sensor 11. At block 1518,the planter monitor 1005 preferably determines the velocity of a rowunit 10-1 using a relation such as:

V ₁ =V _(c) +wD ₁

It should be appreciated that the methods disclosed herein fordetermining a ground speed St of each seed conveyor effectivelydetermine a row-unit-specific speed. Thus the row-unit-specific speedcould also be used to implement a desired application rate in implementshaving sectional or row-by-row application rate control. For example, insome embodiments the meter drive motor 27 is driven at a rate based uponthe row-unit-specific speed determined by one or more of the methodsdescribed herein with respect to FIG. 9D, rather than based upon thetractor speed reported by GPS or radar as is conventional. It should beappreciated that the increase in application rate accuracy resultingfrom the use of a row-unit-specific speed is most significant when theimplement is executing a turn or otherwise traveling in a curvilinearpath. It should also be appreciated that such use of a row-unit-specificspeed to control application rate could be implemented in row unitswithout a seed conveyor (e.g., using a conventional seed tube ordepositing seeds directly from the metering device into the seedtrench).

The foregoing description is presented to enable one of ordinary skillin the art to make and use the invention and is provided in the contextof a patent application and its requirements. Various modifications tothe preferred embodiment of the apparatus, and the general principlesand features of the system and methods described herein will be readilyapparent to those of skill in the art. Thus, the present invention isnot to be limited to the embodiments of the apparatus, system andmethods described above and illustrated in the drawing figures, but isto be accorded the widest scope consistent with the spirit and scope ofthe appended claims.

1. A seed delivery apparatus to deliver seed to a planting surface,comprising: a seed meter configured to entrain and release the seed froma seed disc at a seed release location; a seed conveyor disposed toreceive the seed after the seed is released from said seed disc at anupper end of said seed conveyor, said seed conveyor including a beltconfigured to convey the seed from said upper end to a lower end of saidseed conveyor and release the seed with a rearward velocity relative tosaid seed conveyor; and a first loading wheel disposed adjacent to saidseed release location, said loading wheel being driven for rotation,wherein said loading wheel is disposed to urge the seed toward the belt.2. The seed delivery apparatus of claim 1, further including: a surfacedisposed to guide the seed toward said first loading wheel.
 3. The seeddelivery apparatus of claim 1, further including: a second loading wheeldisposed adjacent to said first loading wheel such that a gap betweensaid first loading wheel and said second loading wheel is disposedadjacent to said seed release location.
 4. The seed delivery apparatusof claim 3, further including: a surface disposed to guide the seedtoward said gap.
 5. The seed delivery apparatus of claim 3, wherein saidfirst loading wheel is compressed radially as the seed enters said gap.6. The seed delivery apparatus of claim 3, wherein said first loadingwheel and said second loading wheel are disposed to eject the seed alonga seed path.
 7. The seed delivery apparatus of claim 6, wherein saidseed path intersects a descending portion of said belt.
 8. The seeddelivery apparatus of claim 6, wherein the seed freefalls along saidseed path.
 9. The seed delivery apparatus of claim 2, wherein the seedtravels in a circular seed path while entrained on said seed disc, andwherein said surface intersects said circular seed path.
 10. The seeddelivery apparatus of claim 1, further including: a motor configured todrive an output gear; a first loading wheel drive gear configured todrive said first loading wheel; and a conveyor drive gear configured todrive said belt, wherein said motor operably drives said first loadingwheel drive gear, and wherein said motor operably drives said conveyordrive gear.
 11. The seed delivery apparatus of claim 10, furtherincluding: a second loading wheel disposed adjacent to said firstloading wheel such that a gap between said first loading wheel and saidsecond loading wheel is disposed adjacent to said seed release location;and a second loading wheel drive gear configured to drive said secondloading wheel, wherein said motor operably drives said second loadingwheel drive gear and wherein said motor operably drives said conveyordrive gear.
 12. The seed delivery apparatus of claim 11, wherein saidfirst loading wheel has a first tangential speed at an outer perimeterof the first loading wheel, wherein said second loading wheel has asecond tangential speed at an outer perimeter of the second loadingwheel, and where said first tangential speed is approximately equal tosaid second tangential speed for each speed of said motor.
 13. The seeddelivery apparatus of claim 11, further including: a surface disposed toguide the seed toward said gap.
 14. The seed delivery apparatus of claim12, wherein said first loading wheel is compressed radially as the seedenters said gap.
 15. The seed delivery apparatus of claim 1, furtherincluding a seed sensor disposed to detect passing seeds on the belt.16. The seed delivery apparatus of claim 15, further including: a firstsidewall disposed laterally adjacent to said belt on a first side, saidfirst sidewall having a first sensor opening; and a second sidewalldisposed laterally adjacent to said belt on a second side, said secondsidewall having a second sensor opening substantially aligned with saidfirst sensor opening, wherein said seed sensor comprises an opticaltransmitter mounted to the first sidewall and an optical receivermounted to the second sidewall, said optical transmitter being disposedto send an optical signal through said first sensor opening and saidsecond sensor opening, said optical receiver being disposed to receivesaid optical signal.
 17. A method of delivering a seed from a seed meterto a planting surface, comprising: capturing a seed with the seed meter;driving a seed conveyor; releasing the seed; capturing the seed betweena first loading wheel and a second loading wheel; ejecting the seed frombetween the first loading wheel and the second loading wheel; receivingthe seed in a seed conveyor; conveying the seed to a lower end of saidseed conveyor; and releasing the seed onto the planting surface.
 18. Themethod of claim 17, further including: decreasing a horizontal velocityof the seed by allowing the seed to travel along a surface disposed at alower end of said seed conveyor.
 19. The method of claim 18, whereinsaid seed conveyor includes a belt having flights.
 20. The method ofclaim 18, wherein the seed is released at a seed release location,wherein the seeds are captured between the first loading wheel and thesecond loading wheel at a seed capture location, and wherein the seedrelease location is located above and adjacent to the seed capturelocation.